<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        a:link{
            color: darkorange;
        }
        a:visited{
            color: darkorchid;
        }

        a:hover{
            color: darkseagreen;
        }
        a:active{
            color: dimgray;
        }

    </style>
</head>
<body>
    <a href="http://www.baidu.com">这是一个链接</a>
</body>
</html>